1. Field of Use
The present invention relates to couplings between beams and supporting uprights and is particularly relevant to jointing colliery roadway supports.
Three piece supports are used in mines for supporting roofs comprising of an `I` section crown beam supported by an `I` section leg at each end. The leg and crown beams may be the same or differing sizes and the legs may be upright or inclined at an angle.
For the purpose of defining the couplings of the invention an `I` beams has a central web connecting two opposed flanges, each flange having essentially five edges that is a pair of `inner` edges meeting the central web, a pair of `minor` edges more or less parallel to the central web and extending between the `inner` edge to a single planar `outer` edge at 90.degree. to the central web.
2. Description of the Prior Art
Coupling beams and uprights has been achieved in the past by means of a steel coupling made in two halves and grooved so as to fit the flanges on both sides of the leg and crown beams at the joint. To connect the halves of the clip together a bolt has been provided which bolts the clip to one side of the leg and below the crown beam. Such an arrangement is unsatisfactory due to the tendency of the clip to open up under strain in the areas remote from the coupling bolt.
The connection of shaped beam members together is also discussed in British patent specification No. 558,909. This specification shows a light clip type connection for coupling the members of a greenhouse together but the clip construction is unsatisfactory for the high stress usage in the present application due to the lack of wrap around of the clip in the immediate area of the junction between members to be joined.